The use of fiber optic proximity probes utilizing bifurcated fiber optic bundles and sensors and detectors to determine the distance to a target are well known. Such devices utilize a light beam transmitted from a light source by way of a bundle of light conducting optical fibers (transmit fibers) from a light source to a target. The light is reflected off the target and returned along other optical fibers (receive fibers) in the bundle back to a light intensity sensor. The intensity of the returned light is a function of the distance between the proximity probe tip and the target, so the output of the light sensor can be a very precise measure of that distance, or more importantly changes in that distance. Such a system is shown and described in U.S. Pat. No. 3,940,608 in which an extender lens is utilized.